In Bohr's model of the hydrogen atom the ratio between the period of revolution of an electron in the orbit n=1 to the period of revolution of the electron in the orbit n=2 is
1. 1:2
2. 2:1
3. 1:4
4. 1:8
A cricket ball of 0.5 kg is moving with a velocity of 100 ms-1. The wavelength associated with its motion is:
1. 1/100cm
2. 6.6 x 10-34m
3. 1.32 x 10-35m
4. 6.6 x 10-28m
The number of electrons in 19 K with quantum numbers n=3; l=0 is/are:
1. 2
2. 1
3. 4
4. 3
The ratio of the difference in energy between the first and second Bohr orbit of H to that between the second and the third Bohr orbit is
1. 1/2
2. 1/3
3. 4/9
4. 27/5
The number of orbitals that are possible at the L-energy level is
1. 2
2. 4
3. 6
4. 1
The radius of second stationary orbit in Bohr's atom is R. The radius of 3rd orbit will be:-
1. 9R
2. R/4
3. 9R/4
4. 2R
Which of the following is not correctly matched?
1. Energy associated with Bohr's orbit E =
2. Energy gap between two orbits
3. Kinectic energy of the ejected electron hv = hv0 + 1/2mv2
4. Energy of one mole of photons E = N0hv/C
If the velocity of a particle is reduced to 1/3rd, then percentage increase in its de-broglie wavelength will be:-
1. 100%
2. 200%
3. 50%
4. 33.33%
The magnetic moment order is correctly given in
1. Fe2+ < Fe3+ < Mn4+ < Cr3+
2. Cr3+ = Mn4+ < Fe2+ < Fe3+
3. Cr3+ = Mn4+ < Fe3+ < Fe2+
4. Fe2+ < Cr3+ < Fe3+ < Mn4+
Bohr's model is not valid for:-
1. H-atom
2. D-atom
3. T-atom
4. He-atom